神农架大九湖泥炭湿地水汽通量特征及生态意义  

Characteristics of Water Vapor Flux and Their Ecological Significance in the Peat Wetlands of Dajiuhu,Shennongjia

作　　者：彭凤姣 葛继稳[1,2,3] 李永福[1,2,3] 李艳元[1,2,3] 程腊梅 张志麒 

机构地区：[1]中国地质大学(武汉)盆地水文过程与湿地生态恢复学术创新基地,湖北武汉430074 [2]中国地质大学(武汉)湿地演化与生态恢复湖北省重点实验室,湖北武汉430074 [3]中国地质大学(武汉)生态环境研究所,湖北武汉430074 [4]武汉伟特伦生态环境研究所,湖北武汉430079 [5]湖北神农架国家湿地公园管理局科研所,湖北神农架林区大九湖乡442417

出　　处：《安全与环境工程》2017年第5期1-8,59,共9页Safety and Environmental Engineering

基　　金：环境保护部生态环境十年变化遥感调查与评估项目(2012046151;2012046395);中国地质大学(武汉)中央高校基本科研业务费专项项目(1323521225;1323521325)

摘　　要：采用涡度相关法对神农架大九湖泥炭湿地生态系统2015年8月至2016年7月的水汽通量进行观测,研究了大九湖湿地水汽通量的变化规律及其主要环境影响因子。结果表明:大九湖湿地水汽通量具有明显的日变化和季节变化,均呈单峰曲线,即在月尺度上,日变化范围为-0.63(5月份)~6.95(7月份)mmol/(s·m^2),白天变化幅度较大,夜间基本维持在0左右,在季节尺度上,夏季日变化最为明显,冬季最弱,生态系统整体表现为水汽源;大九湖湿地全年蒸散量(1 133.88mm)占降雨量(2 096.97mm)的54.07%,表明降雨量能满足目前生态系统的需求;大九湖湿地水汽通量主要受净辐射(Rn)和饱和水汽压差(VPD)的共同影响,即湿地春、夏、秋、冬四季水汽通量与Rn两者拟合的R^2值分别为0.682 3、0.753 4、0.638 4、0.284 7,均优于其他研究区域,可能与泥炭湿地常年积水以及亚高山地区辐射较强有关;大九湖湿地植物主要生长季内(6~9月份)水汽通量与VPD的相关性分析显示,在泥炭藓生长季初期和末期(6、7、9月份),其叶片易受到水分胁迫,水汽通量随VPD先增加后减小,而在泥炭藓生长季中期(8月份),其发育成熟,水汽通量随VPD的增加而增大,两者的拟合效果也达到最佳(R^2=0.408 4)。该研究结果可为该区域水热评估及气候预测提供基础数据。By adopting eddy covariance technique, this paper analyzes the water vapor flux and its controlling envi- ronmental factors from August 2015 to July 2016 in the peat wetlands of Dajiuhu,Shennongjia,which can provide the scientific data for hydrothermal assessment and climate prediction in the region. The results show that the water vapor flux had distinct diurnal and seasonal variations marked by a single-peak type. Daily changes ranged from --0.63 mmol/（s · m^-1 ） （May） to 6.95 mmol/（s ·m2） （July） ,and great changes happened during the daytime,and kept 0 at nighttime. Of four seasons, greatest changes happened in summer, and the change amplitude of winter isthe lowest. On the whole,Dajiuhu peat ecosystem was the source of water vapor. The annual evapotranspiration （1133. 88 mm） accounted for 54.07% of the precipitation （2 096.97 mm）. In addition,evapotranspiration was less than precipitation in the most of months, which indicated that the precipitation can meet the water demands of Daji- uhu peat ecosystem. The water vapor flux is mainly controlled by the net radiation （Rn） and the vapor pressure def- icit （VPD）. There was a good correlation between water vapor flux and Rn, and the squares of coefficients （R2） were 0.682 3 in spring,0.753 4 in summer,0. 638 4 in autumn and 0.284 7 in winter. Our results were better than those of the other study area, which might result {rora the perennial water and strong radiation in the Dajiuhu area. In the early and late growth of Sphagnum （June,July,September）, water vapor flux first increased then decreased with the increase of VPD for Sphagnum leaves were susceptible to water stress. During the middle of the growing season （August）,the physiological condition of Sphagnum was mature, and water vapor flux increased with the in- crease of VPD,showing the best fitting effect （R2 =0.408 4）.

关 键 词：大九湖泥炭湿地 涡度相关法 水汽通量 生态意义 净辐射 饱和水汽压差 

分 类 号：X143[环境科学与工程—环境科学]